From 18eb53a2734ff61b9a72c4fef5db7b38cb48ae16 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Tue, 18 Jun 2024 12:15:01 +0100
Subject: [PATCH] btrfs: don't BUG_ON() when 0 reference count at
btrfs_lookup_extent_info()
commit 28cb13f29faf6290597b24b728dc3100c019356f upstream.
Instead of doing a BUG_ON() handle the error by returning -EUCLEAN,
aborting the transaction and logging an error message.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[Minor conflict resolved due to code context change.]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/extent-tree.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9040108eda64..5395e27f9e89 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -179,6 +179,14 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
ei = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
num_refs = btrfs_extent_refs(leaf, ei);
+ if (unlikely(num_refs == 0)) {
+ ret = -EUCLEAN;
+ btrfs_err(fs_info,
+ "unexpected zero reference count for extent item (%llu %u %llu)",
+ key.objectid, key.type, key.offset);
+ btrfs_abort_transaction(trans, ret);
+ goto out_free;
+ }
extent_flags = btrfs_extent_flags(leaf, ei);
} else {
ret = -EINVAL;
@@ -190,8 +198,6 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
goto out_free;
}
-
- BUG_ON(num_refs == 0);
} else {
num_refs = 0;
extent_flags = 0;
@@ -221,10 +227,19 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
goto search_again;
}
spin_lock(&head->lock);
- if (head->extent_op && head->extent_op->update_flags)
+ if (head->extent_op && head->extent_op->update_flags) {
extent_flags |= head->extent_op->flags_to_set;
- else
- BUG_ON(num_refs == 0);
+ } else if (unlikely(num_refs == 0)) {
+ spin_unlock(&head->lock);
+ mutex_unlock(&head->mutex);
+ spin_unlock(&delayed_refs->lock);
+ ret = -EUCLEAN;
+ btrfs_err(fs_info,
+ "unexpected zero reference count for extent %llu (%s)",
+ bytenr, metadata ? "metadata" : "data");
+ btrfs_abort_transaction(trans, ret);
+ goto out_free;
+ }
num_refs += head->ref_mod;
spin_unlock(&head->lock);